Intangible assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Intangible Assets, Net [Abstract]
Definite-Lived Intangible Assets, Accumulated Amortization	$ 1,874		$ 1,874		$ 1,337
Total Intangible Assets, Gross Carrying Amount	44,805		44,805		44,877
Total Intangible Assets, Net Carrying Amount	42,931		$ 42,931		$ 43,540
Weighted average remaining amortization period for intangible assets			38 years		38 years 9 months 18 days
Amortization	282	$ 286	$ 552	$ 564
Easements [Member]
Intangible Assets, Net [Abstract]
Indefinite-Lived Intangible Assets, Carrying Amount	1,168		1,168		$ 1,161
Shannon LNG Leases and Permits [Member]
Intangible Assets, Net [Abstract]
Definite-Lived Intangible Assets, Gross Carrying Amount	42,078		42,078		42,157
Definite-Lived Intangible Assets, Accumulated Amortization	1,709		1,709		1,198
Definite-Lived Intangible Assets, Net Carrying Amount	40,369		$ 40,369		$ 40,959
Definite-Lived Intangible Assets, Weighted Average Life			40 years		40 years
Easements [Member]
Intangible Assets, Net [Abstract]
Definite-Lived Intangible Assets, Gross Carrying Amount	1,559		$ 1,559		$ 1,559
Definite-Lived Intangible Assets, Accumulated Amortization	165		165		139
Definite-Lived Intangible Assets, Net Carrying Amount	$ 1,394		$ 1,394		$ 1,420
Definite-Lived Intangible Assets, Weighted Average Life			30 years		30 years